Cable Tester | Filter Tester | Use the SPECTRAN V6 as a Network Analyzer
How can i use the SPECTRAN V6 as a network analyzer e.g. to test my cables or a band pass filter?
The setup is quite simple, you only need to start the Noise Generator of the SPECTRAN V6 and the Spectrum Zoom block which offers a Reference Trace feature which is made for exactly this test setup. The measurement itself is done in real-time.
After setting up your mission (attached for download) you need to start a standard setup calibration:
- First of all make sure only to use high quallity test cable connected to Rx and Tx
- Add a thru connector (connect Rx and Tx cable together)
- Now start the calibration measurement and generate a new reference trace from the AVERAGE trace (make sure the AVG trace is stable). Name it e.g. as "REV1"
- Add the "REV1" trace to the "View -> Reference Trace" of the Spectrum Zoom block. You now get a second display which shows the measurement difference in dB to the REV1 trace
- Remove the through line and connect the DUT instead
You now get a steady real-time measurement of the cable damping or filter rejection in dB. In addition you might want to start multiple mesurements with different DUTs (see screenshots as an example comparing 3 different filters each with an own color) and save/display each measurement under a new reference trace. It is as simple as that:
You can now use the spectrum zoom feature to have a closer loook to the filter rejection curves of all three band pass filter (red, green blue) within the WiFi frequency range at the same time:
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Quote from AdminTC on 18/03/2021, 12:22You now get a steady real-time measurement of the cable damping or filter rejection in dB.
Can SPECTRAN V6 (e.g. RSA500X) measure (or convert measurements to) S-parameters in complex form (magnitude and phase)?
Do I need SPECTRAN® V6 S-Parameter Kit to measure S-parameters in complex form?
The S-Parameter Kit is required for measuring reflections (in any form).
The Spectran V6 (any model) can output data as raw IQ values which can be used to calculate magnitude and phase, but there is currently no direct support in the software application to visualize or export that. Also there is currently not direct support for generating a VSWR graph.
Quote from mm_dev on 28/04/2023, 10:25can output data as raw IQ values
Could you please clarify how it might work:
1) Tx generator creates linear frequency sweep with known phase. Rx reads and estimates IQ change for each frequency in sequence?
2) Tx generator creates wideband signal with several carriers/IQs. Rx reads and estimates IQ change for several frequencies simultaneously?
Would like to understand how much it would take to scan for example 1000 frequencies in the range 2.0-3.0GHz (with 1MHz spacing).
Thanks in advance!
The Spectran V6 is not a dedicated network analyzer, so it doesn't have automatic comparison of Tx and Rx signals. You configure your Tx signal, measure your Rx signal and compare them in the software however you want (as said, there is no predefined visualization for this specific application).
On the plus side, the V6 is very fast, scanning a 1 GHz range in 1 MHz steps can be done in under a second (depending on settings).
For testing purposes, you can download the RTSA-Suite PRO for free, use the included IQ Signal Generator block to generate an IQ data stream via software and check if that output fits your needs. That is the same output format as would be generated by the Spectran V6.
Sounds like making VNA (S11 only, or even S21 for those with 2 RX) out of Spectran V6 can be a fun project, using script block and directional coupler... (TX to IN, RX to return signal)
It would first need to handle calibration for Directional coupler + cables (loss and phase shift by connecting calibration standards to coupler OUT)
Then by comparing return signal to calibration, we can calculate return loss/VSWR, and by measuring phase shift, we can get impedance/capacitance/impedance
